How to remove rigid body setting from all the objects?
Select rigid body objects run remove operator.

An object is a rigid body if it has a rigid_body property that is not None

is_rigid_body = ob.rigid_body is not None


See Select Active Rigid Body Parts

Script that selects objects if they are a rigid body of a certain type.  Once selected running

bpy.ops.rigidbody.objects_remove()


Will remove the rigid body settings of selected rigid bodies.

Disable the rigid body world

As commented can disable rigid body world.  Cam temporarily disable via

scene.rigidbody_world.enabled = False